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Surface enhanced Raman spectroscopy (SERS) and confocal Raman microscopy are applied to investigate the structure and the molecular arrangement of sub-micron furosemide and polyvinylpyrrolidone (furosemide/PVP) particles produced by spray flash evaporation (SFE). Morphology, size and crystallinity of furosemide/PVP particles are analyzed by scanning electron microscopy (SEM) and X-ray powder diffraction (XRPD). Far-field Raman spectra and confocal far-field Raman maps of furosemide/PVP particles are interpreted based on the far-field Raman spectra of pure furosemide and PVP precursors. Confocal far-field Raman microscopy shows that furosemide/PVP particles feature an intermixture of furosemide and PVP molecules at the sub-micron scale. SERS and surface-enhanced confocal Raman microscopy (SECoRM) are performed on furosemide, PVP and furosemide/PVP composite particles sputtered with silver (40 nm). SERS and SECoRM maps reveal that furosemide/PVP particle surfaces mainly consist of PVP molecules. The combination of surface and bulk sensitive analyses reveal that furosemide/PVP sub-micron particles are formed by the agglomeration of primary furosemide nano-crystals embedded in a thin PVP matrix. Interestingly, both far-field Raman microscopy and SECoRM provide molecular information on a statistically-relevant amount of sub-micron particles in a single microscopic map; this combination is thus an effective and time-saving tool for investigating organic sub-micron composites., Graphical abstract Image 1, Highlights • Continuous production of pharmaceutical sub-micron composite particles via Spray Flash Evaporation. • Confocal Raman microscopy and SERS for structure investigations of organic sub-micron composite particles. • Formation mechanism of pharmaceutical sub-micron composite particles within the Spray Flash Evaporation process.

The goal of this research was to develop and analyse novel Zn-Co-CeO2 protective coatings on steel. Two different sources of ceria (CeO2) particles were employed: commercial powder and synthesized stable colloidal dispersion-sol. The plating solution was agitated by ultrasounds (20 and 30 W cm(-2)) or by magnetic stirrer (300 rpm) during electrodeposition. The CeO2 particles used were characterized by different methods, namely scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD) to compare the morphology, crystallinity and particle size. The morphology of developed composite coatings was analysed by SEM, the preferred texture was calculated based on XRD results and corrosion behaviour was evaluated by electrochemical impedance spectroscopy (EIS) and polarization measurements. Utilizing ultrasounds during electrodeposition resulted in advanced properties of the nanocomposite coatings compared to magnetic stirring. The particle content in the coatings increased to similar to 5 wt% when ultrasounds were applied and ceria sol used as a source of particles. Presence of ceria in composite coatings offered favourable action in corrosion behaviour increasing barrier properties of composite coatings, thereby providing a prolonged lifetime of Zn-Co alloy coatings. The benefit was more pronounced in the case of ceria sol, and deposition at 20 W cm(-2), when values of impedance modulus at low frequencies reached four times higher values after 4 days exposure to 3 wt% NaCl solution than for coatings deposited with magnetic stirring for both ceria source. The lowest value of corrosion current density (2.15 mu A cm(-2)) was determined for Zn-Co-CeO2 (CeO2 sol) composite coatings deposited under 20 W cm(-2) US power.

The development of composite coating with higher dispersive second phase is a crucial goal to achieve its performance against wear. In this respect, an interesting experimental investigation on the behavior of Ni–B–TiO2 sol composite coating towards scratching, sliding and impact loadings was performed. The adhesive strength was determined by progressive scratch test, while the tribological behavior was assessed through rotating and reciprocating sliding tests, as well as the impact-sliding tests. The in-situ formation of TiO2 nanoparticles in Ni–B bath, which is a recently invented technique, significantly improves the scratch response of the composite coating and its abrasive wear resistance. Indeed, the composite coating appears exempt from delamination after both scratch tests and pin-on-disk test, contrary to the pure Ni–B coating. Regarding the impact wear resistance, it was found that the wear severity and damage mechanisms depend strongly on the impact angle, which in turn is controlled by the solicitation type. The SEM observations accompanied with EDS analysis were carried out inside the wear scars to clearly understand the relationship between the surface damage and the contact angle.

Made available in DSpace on 2021-06-25T11:02:05Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-01-01 We have developed a clean route for the modification of polyvinylchloride surface (PVC) with 4-amino-5-hydrazino-1,2,4-triazole-3-thiol molecule. The modification reaction was investigated through Fourier Transform Infrared Spectroscopy (FTIR) and X-ray Photoelectron Spectroscopy (XPS) analysis. According to our findings, S-H groups are responsible to the molecule attachment and nitrogen atoms are directly involved in metal ion coordination. These results are in agreement with the pseudo-second-order kinetic model, which infers that chemisorption is the main mechanism for metal removal. Adsorption isotherms of Cd(II), Cu(II) and Pb(II) follow the Langmuir model and the results indicated that Ns values are 0.39, 0.52 and 0.15 mmol g−1, respectively. The calculated Ømax values for Cu(II), Pb(II) and Cd(II) were 3.93, 2.95 and 1.13, respectively, indicating that three types of complex are formed depending on the adsorbed species. Therefore, it can be concluded that PVC use as adsorbent is feasible since it requires a simple modification reaction with nontoxic and low-cost solvents. Institute of Bioscience of Botucatu-UNESP – Chemistry and Biochemistry Department Botucatu São Carlos Institute of Physics University of São Paulo Departamento de Engenharia de Bioprocessos e Biotecnologia UNESP Institute of Chemistry Federal University of Mato Grosso do Sul, Cidade Universitaria, Campo Grande Institute of Bioscience of Botucatu-UNESP – Chemistry and Biochemistry Department Botucatu Departamento de Engenharia de Bioprocessos e Biotecnologia UNESP

The mechanical and physical properties of biodegradable magnesium (Mg) alloys make them suitable for temporary orthopaedic implants. The success of these alloys depends on their performance in the physiological environment. In the present work, surface modification of Mg-Ca binary alloy by acid pickling for better biomineralization and controlled biodegradation is explored. The corrosion rates of nitric and phosphoric acid treated samples were analysed by conducting electrochemical corrosion tests. In vitro degradation behaviour was studied using immersion test in simulated body fluid (SBF). The sample surfaces were characterized using scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDS), Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). It is seen that acid pickling leads to significant improvement in biomineralization and develop in situ calcium phosphate (CaP) coating on the sample surfaces. In addition, the treated samples recorded a reduced degradation rate in the SBF compared to untreated samples. Thus, acid pickling is suggested as an effective surface treatment method to tailor the biomineralization and degradation behaviour of the Mg-Ca alloy in the physiological environment.

Diffractive microstructured surfaces are nowadays increasingly applied to polymeric parts for aesthetic, security and optical functionalities. However, both the machining of the mould blaze-grating and its replication on plastic are still representing challenging issues, from both the technical and economical points of view. In this work, an innovative process chain based on carbide tools micromilling of mould gratings was developed for mass production of diffractive patterns on injection moulded parts. A micromilling experimental campaign was conducted on a nickel-phosphorus (NiP) thick coating to machine a blaze-grating on the mould surface, evaluating the influence of the cutting parameters on the diffractive surface quality. Subsequently, the microstructures were replicated on ABS, PC and PMMA by injection moulding. The roughness parameters Sk, Spk and Svk were added with the idea that their sum is representative of the polymer replication of regular diffraction grating pattern. Moreover, the effect of the moulded grating surface quality on the optical performance was preliminarily assessed. The obtained results show that the proposed process chain is suitable for low-cost mass production of polymeric parts with diffractive microstructures.

Magnesium has been known as an appropriate biological material on account of its good biocompatibility and biodegradability properties in addition to advantageous mechanical properties. Mg and its alloys are of poor corrosion resistance. Its high corrosion rate leads to its quick decomposition in the corrosive ambiance and as a result weakening its mechanical properties and before it is repaired, it will vanish. The corrosion and degradation rate must be controlled in the body to advance the usage of Mg and its alloys as implants. Different techniques have been utilized to boost biological properties. Plasma electrolytic oxidation (PEO) can provide porous and biocompatible coatings for implants among various techniques. Biodegradable implants are generally supposed to show enough corrosion resistance and mechanical integrity in the body environment. Much research has been carried out in order to produce PEO coatings containing calcium phosphate compounds. Calcium phosphates are really similar to bone mineral composition and present great biocompatibility. The present study deals with the usage of calcium phosphates as biocompatible coatings applied on Mg and its alloys to study the properties and control the corrosion rate.

Reverse Engineering techniques lead to easily obtain, even in case of wide and complex objects, high-resolution 3D models, suitably adoptable in the field of surface analysis and characterization. This research aims to propose innovative quantification and measuring approaches to diagnose and monitor damages affecting artefacts of different nature, from manufacturing to architectural heritage, performing non-destructive analyses with advanced surface metrology instruments and the potential integrations of the existing sectorial standards. General condition assessment is proposed to recognize and classify characterized pathologies by meaningful features in the form of surface imperfections, through the analysis of acquired point clouds. The method is applied to decay phenomena of an architectural artefact.

The properties of materials at the nanoscale open up new methodologies for engineering prospective materials usable in high-end applications. The preparation of composite materials with a high content of an active component on their surface is one of the current challenges of materials engineering. This concept significantly increases the efficiency of heterogeneous processes moderated by the active component, typically in biological applications, catalysis, or drug delivery. Here we introduce a general approach, based on laser-induced optomechanical processing of silver colloids, for the preparation of polymer surfaces highly enriched with silver nanoparticles (AgNPs). As a result, the AgNPs are firmly immobilized in a thin surface layer without the use of any other chemical mediators. We have shown that our approach is applicable to a broad spectrum of polymer foils, regardless of whether they absorb laser light or not. However, if the laser radiation is absorbed, it is possible to transform smooth surface morphology of the polymer into a roughened one with a higher specific surface area. Analyses of the release of silver from the polymer surface together with antibacterial tests suggested that these materials could be suitable candidates in the fight against nosocomial infections and could inhibit the formation of biofilms with a long-term effect.

Low-free-energy surfaces have attracted an intense academic and industrial interest over the last decade. A reduction of the surface free energy (SFE) has been found to enhance self-cleaning, hydrophobic, and non-fouling properties of surfaces, which are highly desirable in many industrial applications. However, tuning the surface chemistry and topography to achieve tailored low free energy surfaces has been found extremely challenging. In this work, we first show that an accurate refinement of the atmospheric plasma technique guarantees a polymeric coating near to the super-hydrophobic regime. Second, by coupling modelling and experimental measurements we suggest a reliable workflow for the surface characterization and smart design. Specifically, the case study proposed in this contest is capable of quantitatively distinguishing the contribution of a Perfluoro Decyl Acrylate (PFDA) coating, and hence decoupling the role of surface chemistry and roughness, in the reduction of the surface free energy of a bare silicon sample. Beyond the specific case study, our results also emphasize that a synergistic combination of models and experiments can unveil the optimal pathway for designing low-free-energy surfaces.

International audience; Silicone and polyurethane are biocompatible materials used for the manufacture of implantable catheters, but are known to induce drug loss by sorption, causing potentially important clinical consequences. Despite this, their impact on the drugs infused through them is rarely studied, or they are studied individually and not part of a complete infusion setup. The aim of this work was to experimentally investigate the drug loss that these devices can cause, on their own and within a complete infusion setup. Paracetamol, diazepam, and insulin were chosen as models to assess drug sorption. Four commonly used silicone and polyurethane catheters were studied independently and as part of two different setups composed of a syringe, an extension set, and silicone or polyurethane implantable catheter. Simulated infusion through the catheter alone or through the complete setup were tested, at flowrates of 1 mL/h and 10 mL/h. Drug concentrations were monitored by liquid chromatography, and the silicone and polyurethane materials were characterized by ATR-IR spectroscopy and Zeta surface potential measurements. The losses observed with the complete setups followed the same trend as the losses induced individually by the most sorptive device of the setup. With the complete setups, no loss of paracetamol was observed, but diazepam and insulin maximum losses were respectively of 96.4 ± 0.9% and 54.0 ± 5.6%, when using a polyurethane catheter. Overall, catheters were shown to be the cause of some extremely high drug losses that could not be countered by optimizing the extension set in the setup.

In recent years in the dental field, new types of materials and techniques for the manufacturing of dental crowns and analog implants have been developed to improve the quality of these products. The objective of this article was to perform the surface characterization and determine the properties of Co-Cr alloy samples fabricated by the direct metal laser sintering (DMLS) process and coated by e-gun technology with thin films of Ta2O5 and ZnO. Both oxides are frequently used for dental products, in pharmacology, cosmetics, and medicine, due to their good anticorrosive, antibacterial, and photo-catalytic properties. Following the deposition of thin oxide films on the Co-Cr samples fabricated by DMLS, a very fine roughness in the order of nanometers was obtained. Thin films deposition was realized to improve the hardness and the roughness of the Co-Cr parts fabricated by the DMLS process. Surface characterization was performed using SEM-EDS, AFM, and XRD. AFM was used to determine the roughness of the samples and the nanoindentation curves were determined to establish the hardness values and modulus of elasticity.

Made available in DSpace on 2020-12-12T00:55:13Z (GMT). No. of bitstreams: 0 Previous issue date: 2019-11-01 Fundação de Amparo à Pesquisa do Estado de Minas Gerais (FAPEMIG) National Institute of Dental and Craniofacial Research Objective: To evaluate the influence of extrinsic pigmentation on the biaxial flexural strength and surface topographic of translucent Y-TZP (InCoris TZI – Sirona – USA) subjected to several surface treatments. Methods: Sintered zirconia discs-shaped specimens (n = 120) (ø:12 mm; thickness:1.2 mm; ISO 6872) were prepared and divided (n = 15) according to various factors: “extrinsic pigmentation” (n: without; p: with) and “surface treatments” (C: control — as sintered; A: abraded with silica-coated alumina particles (30 μm); G: glazed with a thin film of low-fusing porcelain glaze; GH: glazed and etched with 10% hydrofluoridric acid for 60 s. Mechanical cycling (1.2 × 106 cycles, 200 N, 3.8 Hz) and flexural strength test (1 mm/min — 1000 kg cell) were performed. Two-way ANOVA and Tukey's were used for statistical test (α = 0.05). Weibull analysis was used to evaluate the strength reliability. Samples were analyzed via (1) an optical profilometer to determine the surface roughness (Ra); (2) an X-ray diffraction (XRD) to evaluate phase transformations; and (3) a SEM equipped with an energy dispersive X-ray spectroscopy (EDX) to elucidate morphological properties and chemical compositions. Results: Regardless of the surface treatment (p = 0.5459) (Cn: 560.16 MPa; Gn: 573.36 MPa; An: 643.51 MPa; GHn: 542.94 MPa; Cp: 628.04 MPa; Gp: 641.90 MPa; Ap: 554.47 MPa; GHp :602.84 MPa) and extrinsic pigmentation (p = 0.1280) there was no difference in the flexural strength among the experimental groups. According to the XRD analysis, phase transformations occurred in the An group (t → m) and in Ap group (t → c). Surface roughness was affected by surface treatments (An — p = 0.001) and extrinsic pigmentation (Gp — p = 0.001). Significance: The biaxial flexural strength of the tested samples was not affected neither by surface treatments nor by pigmentation, although it can cause phase transformation and promote surface roughness. Department of Restorative Dentistry Federal University of Juiz de Fora (UFJF) Juiz de Fora/MG Department of Dental Materials and Prosthodontics Institute of Science and Technology São Paulo State University – UNESP Federal University of Rio Grande do Norte/UFRN Health Science Center Department of Dentistry New York University College of Dentistry Department of Biomaterials and Biomimetics, 433 First Avenue, Room 810 Department of Dental Materials and Prosthodontics Institute of Science and Technology São Paulo State University – UNESP National Institute of Dental and Craniofacial Research: R01DE026279 National Institute of Dental and Craniofacial Research: R01DE026772

金沢大学理工研究域フロンティア工学系, Friction measurements have been carried out to characterize surface damages during photodegradation of low-density polyethylene. The average and mean deviation of the friction coefficients increase with the irradiation time in the early stage of photodegradation processes, indicating the increase in the surface roughness, whereas the mechanical properties remain essentially unchanged. In the following stage, where the ductile-brittle transition takes place, the mean deviation of the friction coefficients shows an appreciable decrease with maintaining almost constant average values, suggesting that the surface becomes more homogeneous. Beyond the ductile-brittle transition, both of the average and mean deviation of the friction coefficients gradually increase with the irradiation time, indicating further enhancement of surface roughness, followed by formation of surface cracks. The soundness of the friction measurements is confirmed by comparing with optical measurements of the surface roughness, and it is suggested that the present method gives a convenient and sensitive method of detection for degradation in polymeric materials. © 2019 Walter de Gruyter GmbH, Berlin/Boston 2019., Embargo Period 12 months

A simple and fast method for preparing chitosan (CH)/conducting polymer (CP) composite film with and without reduced graphene oxide (rGO) was realized to investigate the effect of rGO on an optoelectrochemical system. For this purpose, firstly rGO was successfully dispersed in the acidic aqueous solution of CH by ultrasonic agitation. One by one CH and CH/rGO blend deposited on an indium tin-oxide (ITO) coated glass electrode by drop-casting method. After that, N1,N4-bis(2,5-di(thiophen-2-yl)-1H-pyrrol-1-yl)terephthalamide (m(BT)) electroactive monomer was deposited onto CH and CH/rGO modified ITO electrode surfaces via electrochemical polymerization. Electrochemical and optical properties of the composite structures were investigated by cyclic voltammetry (CV) technique and UV–vis spectroscopy. The surface characterizations of nanocomposites have been performed by scanning electron microscopy. It was observed that, chemical functionalities of CH, rGO and p(BT) provide excellent compatibility. Therefore, the CH/rGO/p(BT) electroactive nanocomposite has better conductivity, stability, charge density, electrochromic switching kinetics and electrochemical properties than the CH/p(BT) and p(BT)/rGO composites. This is due to more efficient synergistic effect between CH, rGO and p(BT) which provide larger active surface area and ease ion transport. This method for producing composite films with novel optical, electrical and stability properties has been gaining a new perspective in the material world, which enables smart and advanced material design in various practical applications especially for designing molecular detection systems. © 2018 Elsevier Ltd

A review to enrich the literature concerning the effect of various plasmas on the tribological behaviour of polymers and monitor the developments of plasma for the modification of polymer surfaces over recent decades using up-to-date data. A comparative study of plasmas was conducted to identify the most useful and efficient ones which facilitate optimal improvements with regard to the characterizations of polymer surfaces and tribological properties. The studies included in this review strongly suggest that (besides Plasma-Immersion Ion Implantation, PIII) atmospheric plasmas (dielectric barrier discharges, DBD) are an effective technique in terms of modifying the characterizations of polymer surfaces thereby enhancing the tribological behaviour of polymers under different operating conditions that extends the operating life of elements within the machine.

The surface of articular cartilage is integral to smooth, low-friction joint articulation. However, the majority of cartilage literature rarely includes measurements of surface characteristics and function. This may, in part, be due to a shortage of or unfamiliarity with fast, nondestructive, and, preferably, noncontact methods that can be applied to large cartilage surfaces for evaluating cartilage surface characteristics. A comprehensive methodology for characterizing cartilage surfaces is useful in determining changes in tissue function, as for example, in cases where the quality of cartilage grafts needs to be assessed. With cartilage storage conditions being an area of ongoing and active research, this study used interferometry and tribology methods as efficient and nondestructive ways of evaluating changes in cartilage surface topography, roughness, and coefficient of friction (CoF) resulting from various storage temperatures and durations. Standard, destructive testing for bulk mechanical and biochemical properties, as well as immunohistochemistry, were also performed. For the first time, interferometry was used to show cartilage topographical anisotropy through an anterior–posterior striated pattern in the same direction as joint articulation. Another novel observation enabled by tribology was frictional anisotropy, illustrated by a 53% increase in CoF in the medial–lateral direction compared to the anterior–posterior direction. Of the storage conditions examined, 37°C, 4°C, −20°C, and −80°C for 1 day, 1 week, and 1 month, a 49% decrease in CoF was observed at 1 week in −80°C. Interestingly, prolonged storage at 37°C resulted in up to an 83% increase in the compressive aggregate modulus by 1 month, with a corresponding increase in the glycosaminoglycan (GAG) bulk content. This study illustrates the differential effects of storage conditions on cartilage: freezing tends to target surface properties, while nonfreezing storage impacts the tissue bulk. These data show that a bulk-only analysis of cartilage function is not sufficient or representative. The nondestructive surface characterization assays described here enable improvement in cartilage functionality assessment by considering both surface and bulk cartilage properties; this methodology may thus provide a new angle to explore in future cartilage research and tissue engineering endeavors. IMPACT STATEMENT: Cartilage's major functions are load distribution and low-friction articulation. These functions are primarily carried out by the cartilage bulk tissue and surface layer, respectively. Although cartilage bulk properties are frequently assessed, surface characterization is often overlooked despite its importance to proper cartilage function. Toward closing this gap, this study presents cartilage evaluation that uses interferometry, tribology, and lubricin immunohistochemistry for comprehensive surface characterization. In the context of cartilage function preservation after storage, the conditions that alter bulk versus surface characteristics were found to differ, highlighting the importance of assessing surface function for both clinical and tissue engineering applications.

Herein, we investigated the surface characterization and biocompatibility of a denture-lining material containing Cnidium officinale extracts and its antifungal efficacy against Candida albicans. To achieve this, a denture-lining material containing various concentrations of C. officinale extract and a control group without C. officinale extract were prepared. The surface characterization and biocompatibility of the samples were investigated. In addition, the antifungal efficacy of the samples on C. albicans was investigated using spectrophotometric growth and a LIVE/DEAD assay. The results revealed that there was no significant difference between the biocompatibility of the experimental and control groups (p &gt, 0.05). However, there was a significant difference between the antifungal efficiency of the denture material on C. albicans and that of the control group (p &lt, 0.05), which was confirmed by the LIVE/DEAD assay. These results indicate the promising potential of the C. officinale extract-containing denture-lining material as an antifungal dental material.

The test alumina (the so-called ι-Al2O3) was thermally recovered at 1,100°C from chitosan-AlOx hybrid films and found to contain Na and Ca impurity ions inherited from the parent chitosan. Two different modifications of pure alumina, namely, γ- and α-Al2O3, were adopted as control samples. The test and control aluminas were examined for 1) the bulk elemental constitution by atomic absorption spectroscopy (AAS), 2) the surface chemical composition by X-ray photoelectron spectroscopy (XPS), 3) the bulk phase composition by X-ray powder diffractometry (XRD), ex-situ Fourier-transform infrared spectroscopy (IR), and Laser Raman (LRa) spectroscopy, 4) the surface area, topography, and morphology by N2 sorptiometry, and atomic force (AFM) and scanning electron microscopy (SEM), 5) the surface adsorptive interactions with pyridine and 2-propanol gas-phase molecules by in-situ IR spectroscopy of the adsorbed species, and 6) the surface catalytic interactions with 2-propanol gas-phase molecules by in-situ IR spectroscopy of the gas phase. Results obtained could clearly show that the test alumina (ι-Al2O3) is only hypothetically pure alumina since in reality its bulk structure is majored by mullite-type Na-aluminate (Na0.67Al6O9.33/NaAlO2) and minored by Na-β-alumina (Na1.71Al11O17) and β-alumina (NaAl11O17). Consistently, observed Na-influenced modifications of the surface chemistry, topology, and morphology, as well as adsorptive and catalytic interactions with pyridine and 2-propanol gas-phase molecules, showed significant deviations from those exhibited by the control pure aluminas (γ- and α-Al2O3).

Defect-engineered or substoichiometric TiOx is of interest for use in photo- and electrocatalytic processes both as active material and catalyst support. Electrochemical doping of TiO2 via cathodic polarization is an appealing preparation method and frequently employed. Here, we explored the electrochemical preparation of TiOx in an undivided cell using iridium-based (iridium mixed-metal-oxide) and boron doped diamond (BDD) counter electrodes. Cyclic voltammetry and impedance spectroscopy revealed superior charge transfer properties of crystalline TiOx electrodes prepared with BDD (TiOx-BDD). It is shown that the electrochemical properties correlate well with intensities of the H-signals determined using Time of Flight - Secondary Ion Mass Spectrometry (ToF-SIMS). Thus, it is concluded that electrochemical preparation using BDD causes favourable H+ intercalation and/or H diffusion into the sub-surface layers of TiOx. Our extensive analysis using a combination of electrochemical and surface characterization (LEIS and XPS) techniques, additionally suggests that cathodic deposition of Ir, originating from the Ir-based counter electrode, present in sub-ppm concentrations only results in less-efficient doping. Instead in the presence of sub-ppm level Ir contamination hydrogen evolution is favoured during cathodic polarization. The results presented within this study highlight the necessity to use inherently stable counter electrodes for electrochemical preparation and reveal the pronounced influence of trace contamination in electrochemistry in general and the doping mechanism of TiOx electrodes in particular.

In the modern fish processing industry, flat fishes play an important role. They are processed into a final product in the form of a fillet during the skinning operation, which is carried out on machines operating in automated production lines. These machines are usually equipped with a single planar cutting blade or a few of such blades. The high-efficiency skinning and industrial conditions cause rapid wear of the cutting edge of the blade, which is detrimental to the quality of the final product. One of the forms of renewing the cutting ability of these types of tools is the regeneration carried out with the use of precise traverse surface grinding. The results of this process must be carefully verified for determining its correctness and possible optimization of its parameters. The main goal of this article was to characterize the usefulness of a number of observational and measuring methods to evaluate the results of the technical blade regeneration process. In this work, a number of contemporary observation&ndash, measurement methods such as optical microscopy (OM), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), optical profilometry (OP), and angle-resolved scattering (ARS), supported by image processing and analysis techniques, were analyzed. The authors focused on presenting the role of the abovementioned methods in the surface characterization of planar cutting blades made of X39Cr13 chromium martensitic stainless steel before and after the technological operation of flat-fish skinning. Additionally, the surface condition after the regeneration process carried out using the five-axis CNC (computerized numerical control) grinding machine was also assessed. Numerous results of surface observations, elemental composition microanalysis, high-accuracy surface microgeometry measurements, and quantitative and qualitative analysis confirming the possibility of using the proposed methods in the presented applications are presented.

This paper presents wear and corrosion resistance analysis of carbon nanotubes coated with Ti-6Al-4V alloy processed by electro-discharge treatment. The reported work is carried out using Taguchi&rsquo, s L18 orthogonal array to design the experimental matrix by varying five input process parameters i.e., dielectric medium (plain dielectric, multi-walled carbon nanotubes (MWCNTs) mixed dielectric), current (1&ndash, 4 A), pulse-on-time (30&ndash, 60 &micro, s), pulse-off-time (60&ndash, 120 &micro, s), and voltage (30&ndash, 50 V). The output responses are assessed in terms of microhardness and surface roughness of the treated specimen. X-ray diffraction (XRD) spectra of the coated sample reveal the formation of intermetallic compounds, oxides, and carbides, whereas surface morphology is observed using scanning electron microscopy (SEM) analysis. For the purpose of the in-vitro wear behavior of treated samples, the surface with superior microhardness values in plain dielectric and MWCNTs mixed dielectric is compared using a pin-on-disc type wear test. Furthermore, electrochemical corrosion test is also conducted to portray the dominance of treated substrate of Ti-6Al-4V alloy for biomedical applications. It is concluded that the wear-resistant and the corrosion protection efficiency of the MWCNTs treated substrate enhanced to 95%, and 96.63%, respectively.

Starch, an abundant and low-cost plant-based glucopolymer, has great potential to replace carbon-based polymers in various materials. In order to optimize its functional properties for bioplastics applications chemical groups need to be introduced on the free hydroxyl groups in a controlled manner, so an understanding of the resulting structure-properties relationships is therefore essential. The purpose of this work was to study the multiscale structure of highly-acetylated (degree of substitution, 0.4 &lt, DS &le, 3) and etherified starches by using an original combination of experimental strategies and methodologies. The molecular structure and substituents repartition were investigated by developing new sample preparation strategies for specific analysis including Asymmetrical Flow Field Flow Fractionation associated with Multiangle Laser Light Scattering, Nuclear Magnetic Resonance (NMR), Raman and Time of Flight Secondary Ion Mass spectroscopies. Molar mass decrease and specific ways of chain breakage due to modification were pointed out and are correlated to the amylose content. The amorphous structuration was revealed by solid-state NMR. This original broad analytical approach allowed for the first time a large characterization of highly-acetylated starches insoluble in aqueous solvents. This strategy, then applied to characterize etherified starches, opens the way to correlate the structure to the properties of such insoluble starch-based materials.

The ability of poly(vinyl butyral-co-vinyl alcohol-co-vinyl acetate) (PVBVA) to consolidate Fir wood was studied in terms of the surface and mechanical properties&rsquo, changes. Two variables were considered to treat the wood: (i) the concentration (5 and 10 wt.%) of PVBVA solutions and (ii) the method of application (brushing and immersion). The presence of PVBVA on the wood surfaces was confirmed by infrared spectroscopy. Surface roughness measured by optical profilometry did not reveal changes in the topography of the samples, and appropriate visual appearance was confirmed. Contact angle measurements showed that a droplet of the 10%-PVBVA solution needed 50 s to reach the same contact angle decreasing rate as that measured for the 5%-PVBVA solution, suggesting there was some kind of induction time till the spreading process was no longer controlled by the viscosity, but by the solution-wood interactions. Water contact angle (WCA) measurements proved a more hydrophobic surface of the PVBVA-treated samples, compared to untreated wood. Mechanical characterization of the samples was done macroscopically by a three-point bending test and locally by the Shore D and Martens hardness (MH). Only results from MH experiments provided comparative results, indicating that treatment with PVBVA solutions increased wood hardness locally, being enhanced with solution concentration. The best surface mechanical properties were obtained for the samples immersed in the 10%-PVBVA solution.

We report on an experimental study and statistical optimization of the surface roughness using design of experiments and the Taguchi method for parts made of 1.2709 maraging steel. We employ a hybrid additive manufacturing approach that combines additive manufacturing by selective laser melting with subtractive manufacturing using milling in an automated process within a single machine. Input parameters such as laser power, scan speed, and hatching distance have been varied in order to improve surface quality of unmachined surfaces. Cutting speed, feed per tooth, and radial depth of cut have been varied to optimize surface roughness of the milled surfaces. The surfaces of the samples were characterized using 3D profilometry. Scan speed was determined as the most important parameter for non-machined surfaces, radial depth of cut was found to be the most significant parameter for milled surfaces. Areal surface roughness S a could be reduced by up to 40% for unmachined samples and by 23% for milled samples as compared to the prior state of the art.

In vitro electrochemical characterization and in vivo implantation in an animal model were employed to evaluate the degradation behavior and the biological activity of FeMnSi and FeMnSiCa alloys obtained using UltraCast (Ar atmosphere) melting. Electrochemical characterization was based on open circuit potential measurement, electrochemical impedance spectroscopy and potentiodynamic polarization techniques while the alloys were immersed in Ringer’s solution at 37 ºC for 7 days. Higher corrosion rates were measured for the Ca-containing material, resulting from inefficient passivation of the metal surface by oxy-hydroxide products. In vivo osseointegration was investigated on a tibia implant model in rabbits by referring to a standard control (AISI 316L) stainless steel using standard biochemical, histological and radiological methods of investigation. Changes in the biochemical parameters were related to the main stages of the bone fracture repair, whereas implantation of the alloys in rabbit’s tibia provided the necessary mechanical support to the injured bone area and facilitated the growth of the newly connective tissue, as well as osteoid formation and mineralization, as revealed by computed tomography reconstructed images and validated by the bone morphometric indices. The present study highlighted that the FeMnSiCa alloy promotes better osteoinduction and osseointegration processes when compared to the base FeMnSi alloy or with AISI 316L, and in vivo degradation rates correlate well with corrosion resistance measurements in Ringer’s solution.

Subsurface grains of Alloy 718 additively manufactured via electron beam-powder bed fusion technique were refined using shot peening to improve the surface texture and oxidation performance. Oxidation of the specimens was performed at 650 and 800 degrees C in ambient air. Due to plastic deformation upon shot peening, compressive residual stress and high microstrain were generated in the subsurface region within a depth of approximately 50 mu m. The shot-peened specimen exhibited lower surface roughness, finer subsurface grains, and higher hardness compared to the as-built specimen. Shot peening, coupled with hot isostatic pressing and heat treatment (HIP-HT), yielded superior oxidation performance with substantially low oxidation kinetics at 800 degrees C. The smooth surface, as well as dense and refined subsurface microstructure resulting from shot peening, facilitated the formation of a continuous, protective, and adherent Cr-rich oxide scale. Financial supports of the Knowledge Foundation for the SupREme project (Dnr 20180203) and Aforsk for the SCC-SUMAN project (18-296) are highly acknowledged. The authors would like to thank Mr. Jonas Olsson, Dr. Mahdi Eynian, and Prof. Joel Andersson for their valuable help and advice in processing and characterization of the specimens. The authors would like to thank Mr. Olle Widman from Curtiss-wright Surface Technologies for shot peening, Mr. Johannes Gardstam, and Mr. James Shipley from Quintus Technologies AB for HT-HIPing of the specimens. The authors are grateful to Venkataramanan Mohandass for the characterization of the specimens. Chalmers Materials Analysis Laboratory (CMAL) at the Chalmers University of Technology are appreciated for the help in the XRD/SEM analysis.

International audience; Many composite forming processes are based on the consolidation of preimpregnated preforms of different types, e.g., sheets, tapes, .... Composite plies are put in contact using different technologies and consolidation is performed by supplying heat and pressure, the first to promote molecular diffusion at the plies interface and both (heat and pressure) to facilitate the intimate contact by squeezing surface asperities. Optimal processing requires an intimate contact as large as possible between the surfaces put in contact, for different reasons: (i) first, a perfect contact becomes compulsory to make possible molecular diffusion at the interface level in order to ensure bulk properties at interfaces; (ii) second, imperfect contact conditions result in micro and meso pores located at the interface, weakening it from the mechanical point of view, where macro defects (cracks, plies delamination, etc.) are susceptible of appearing. As just indicated, the main process parameters are the applied heat and pressure, as well as the process time (associated with the laying head velocity). These parameters should be adjusted to ensure optimal consolidation, avoiding imperfect bonding or thermal degradation. However, experiments evidence that the consolidation degree is strongly dependent on the surface characteristics (roughness). The same process parameters applied to different surfaces produce very different degrees of intimate contact. The present study aims at identifying the main surface descriptors able to describe the evolution of the degree of intimate contact during processing. That knowledge is crucial for online process control in order to maximize both productivity and part quality.

Cancer is one of the most serious public health problems that affect humanity. Diverse delivery systems of anticancer drugs have been developed to enhance the treatment effectiveness and patient compliance. Thus, drug delivery systems from polymeric films could be an interesting and promising alternative, especially for skin chemotherapeutics. In this work, polymeric films based on glutathione-chitosan conjugates with degrees of thiolation of 4.4%, 5.1% and 7.0% were synthetized by casting-evaporation method and subsequent loading with methotrexate. The surface properties of these films were evaluated by contact angle and spreading rate measurements. The sessile drop methods along with the thermodynamic parameter of work of adhesion were determined using the Young&ndash, Dupr&eacute, semi-empirical model. The in vitro methotrexate release was assessed at a pH of 4.5 and 7.4 simulating physiological conditions. Data from the resulting profiles were fitted to the order one, Higuchi, Peppas&ndash, Sahlin and Korsmeyer&ndash, Peppas kinetic models. The results suggest a strong relationship between the thiolation degree and hydrophilic surface properties such as contact angle and water spreading rate, whereas the work of adhesion was not significantly affected. Further, these polymer films could control the methotrexate release through diverse mechanisms such as diffusion and relaxation depending on the thiolation degree and the aqueous medium employed. In fact, as thiolation degree increased, the release mechanism shifted from a primary diffusional type towards a predominant relaxation-driven mechanism. These polymer films could be used as modified systems for anticancer local delivery.

The generation of surface free energy parameters calculated from contact angle data is a burdensome and time-consuming process. To facilitate these calculations, computational algorithms using three different programming languages—MATLAB, C and Python—were developed and validated by surface properties determination of PO and CPO. The results indicated that the surface free energy parameters calculated using the three algorithms were consistent. The unknowns were obtained directly from within the C and Python programs, however, indirectly from within MATLAB function. In addition, the assembly statements of the C function were longer than those of the other two. The obtained results were also compared with those from an IGC analysis. It showed that the γ S D values determined using the contact angle methods were consistent, although lower than those obtained by IGC analysis. Compared to γ S D , the γ S S P component contributed less to γ S T . The lower γ S D and γ S S P values for CPO which added up to a lower γ S T value, could reduce filler particle/particle interactions, allowing a better dispersion in a polymer matrix.

The goal of this study was to use a novel surface chemistry for modifying gold surfaces to decrease the steric hindrance, minimize the nonspecific bindings while providing directed immobilization of proteins for advancing the transducer property and to provide a biosensing platform for surface plasmon resonance (SPR) applications. Mixed self-assembled monolayers (mSAMs) were prepared using 3,3′-Dithiodipropionic acid di (N-hydroxysuccinimide ester) (DSP) and 6-mercapto-1-hexanol (MCH) and the selected model proteins bovine serum albumin (BSA) and lysozyme were tested for binding efficiency. First, binding of these two proteins at constant concentration to different DSP:MCH mSAMs were compared to deduce the best molar ratio for forming mSAM using a continuous flow system coupled to SPR. Coincidently the maximum protein binding DSP:MCH mSAM were the same for both proteins. The change in Response Unit (∆RU) signal due to protein binding between DSP SAM and maximum protein binding DSP:MCH mSAM for lysozyme binding was more in comparison to BSA binding. Second, the effect of BSA and lysozyme concentration on binding efficiency to maximum protein binding DSP:MCH mSAM were compared and discussed. Lysozyme and BSA were shown to reach saturations on the same monolayer at concentrations of 5.7x10−5 and 8.96x10−6 [M] respectively, hence the molar ratio for limit concentrations is 6:1. The DSP SAM, MCH SAM, and DSP:MCH mSAMs where maximum and minimum protein binding occurs were also characterized with XPS and Attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy. Blank gold surface, maximum protein binding DSP:MCH mSAM and BSA immobilized DSP:MCH mSAM on gold surface were also investigated utilizing tapping mode AFM., US-Egypt Joint Board on Scientific and Technological Cooperation

Ceria-zirconia mixed oxides are widely used as catalysts and catalytic supports. Nevertheless, due to economic and geo-strategic concerns, reducing and optimizing the lanthanide content in these formulations while preserving or even improving their excellent redox and catalytic properties has become a challenge for current research. In this context, the design of core@shell nanostructures arises as a feasible alternative to achieve the aforesaid goal. In the present work, a new nanostructured ZrO2@CeO2 system based on spherical and mesoporous zirconia cores coated by a well-dispersed nanometer-thick ceria layer has been prepared by a novel synthetic approach in 2 different steps: (1) synthesis of the zirconia cores by a sol-gel method and (2) coating with a thin ceria shell by controlled chemical precipitation. The resulting nanocomposite was characterized by several techniques, which clearly reveal its perfect core@shell nanostructure and enhanced reducibility as compared with pure ceria.

We present a study of sulfonitric treatment and its effect on MWCNTs at different temperatures (90, 110, 130 and 150ºC) using DRX, XPS, FTIR, Raman spectroscopy, TEM and zeta potential. It was found that oxidation starts with the C-C and C-H bonds generating different oxidized groups from alcohol to carboxylic acid, following a sequential oxidation. Given that heterocoagulation needs a maximum zeta potential gap between the ceramic and the MWCNT surface and it significantly exist a risk of manipulate acids at high temperature it is recommended to use acid treatment of CNT at 110 ºC for generating ceramic composites by heterocoagulation., Facultad de Ciencias Exactas, Centro de Tecnología de Recursos Minerales y Cerámica

SARS-CoV-2, the cause of COVID-19, is a new, highly pathogenic coronavirus, which is the third coronavirus to emerge in the past 2 decades and the first to become a global pandemic. The virus has demonstrated itself to be extremely transmissible and deadly. Recent data suggest that a targeted approach is key to mitigating infectivity. Due to the proliferation of cataloged protein and nucleic acid sequences in databases, the function of the nucleic acid, and genetic encoded proteins, we make predictions by simply aligning sequences and exploring their homology. Thus, similar amino acid sequences in a protein usually confer similar biochemical function, even from distal or unrelated organisms. To understand viral transmission and adhesion, it is key to elucidate the structural, surface, and functional properties of each viral protein. This is typically first modeled in highly pathogenic species by exploring folding, hydrophobicity, and isoelectric point (IEP). Recent evidence from viral RNA sequence modeling and protein crystals have been inadequate, which prevent full understanding of the IEP and other viral properties of SARS-CoV-2. We have thus experimentally determined the IEP of SARS-CoV-2. Our findings suggest that for enveloped viruses, such as SARS-CoV-2, estimates of IEP by the amino acid sequence alone may be unreliable. We compared the experimental IEP of SARS-CoV-2 to variants of interest (VOIs) using their amino acid sequence, thus providing a qualitative comparison of the IEP of VOIs.

Surface modification of titanium-based implants has been extensively researched as an effective tool to generate a bioactive surface that helps to create a new bone and forms a natural bond at the interface between the implants and surrounding bone tissues. The present research is focused on the development of a new methodology to obtain sphene (CaTiSiO 5 ) biocoatings on titanium substrates. Based on previous results, where sphene coatings were obtained by a manual airbrush, the coating system was improved in order to have a full control of the process in terms of uniform morphology of the biocoating. The effectiveness of the coating system and deposition process is supported by microscopic analysis of the produced coatings, by surface roughness measurements of uncoated and coated substrates, and estimation of the adhesion strength between the coatings and the substrate. The results showed that the coatings had crack-free homogenous surfaces with ideal characteristics for orthopedic and dental implants in terms of adhesion strength and surface roughness.

Fly ash from power plants is very toxic because it contains heavy metals. In this study fly ash was treated with a thermal plasma. Before their treatment, the fly ash was analyzed by many technics such as X-ray fluorescence, CHN elemental analysis, inductively coupled plasma atomic emission spectroscopy and scanning electron microscopy. With these technics, the composition, the chemical and physical proprieties of fly ash are determined. The results obtained by these analysis show that fly ash is mainly composed of carbon, and it contains also sulfur and metals such as V, Ca, Mg, Na, Fe, Ni, and Rh. The scanning electron microscopy analysis shows that fly ash particles are porous and have very irregular shapes with particle sizes of 20–50 μm. The treatment of fly ash was carried out in a plasma reactor and in two steps. In the first step, fly ash was treated in a pyrolysis/combustion plasma system to reduce the fraction of carbon. In the second step, the product obtained by the combustion of fly ash was vitrified in a plasma furnace. The leaching results show that the fly ash was detoxified by plasma vitrification and the produced slag is amorphous and glassy.

Boron industrial solid waste is used as reinforcement for preparing composite materials. This waste has boron trioxide which holds unique properties may affect the surface or interface of the composite. The prepared composites are characterized in order to determine the dispersion and the structure by means of inverse gas chromatography (IGC), Fourier transform infrared spectroscopy, thermal gravimetric analysis, scanning electron microscopy (SEM) and X-ray diffraction (XRD). There is a strong relation between the dispersion of reinforcement and the properties of newly formed composite. The dispersive component of the surface energies of the composites and components are determined by IGC. This parameter is difficult to measure by other methods and it is related to the wettability and adhesive characters of solid materials. The effect of compounding ratios of reinforcement is also examined. Furthermore, XRD diffractograms and SEM images of composites showed well dispersion. Thermal analysis revealed that the addition of the boron industrial solid waste to the polymer increased the thermal stability of pure polymer. Infrared spectra of the composites indicated that the composites were formed from the waste reinforcement and the polymer matrix., The Scientific Research Fund of Eskişehir Osmangazi University [grant number 201015040]

We have irradiated with Au ions (having an energy of 250 MeV) epitaxial thin films of BaFe2(As(1-x)P(x))2 with x @ 0.2 (optimal doping), grown by MBE on MgO single-crystal substrates. We have studied the effects of irradiation (for three different fluences, F=2.4×10^11 cm^-2, 4.8×10^11 cm^-2 and 7.3×10^11 cm^-2) on the surface morphology, on the resistivity and on the critical temperature. We have found that irradiation progressively destroys the very clear and interconnected growth terraces typical of the pristine surface, leading first to their smoothing - accompanied by the appearance of localized defects and cracks - and then to a completely disordered surface. However, the resistivity increases only slightly and the critical temperature decreases very little (i.e. by about 2%) going from the pristine film to the most-irradiated one. The latter result is confirmed by local measurements of the critical temperature carried out by point-contact Andreev reflection spectroscopy.

The laser marking of acrylonitrile–butadiene–styrene filled with carbon black was studied using either an infrared or ultraviolet laser. The influence of the amount of additive on the final contrast of marks was studied for the two differentiated wavelengths. Both lasers exhibit different marking mechanisms, according to color properties, topography, and spectroscopic analysis of the marks. The infrared laser induced a thermally foaming effect and the ultraviolet laser seemed to induce a photochemical effect with the polymer matrix and removal of carbon black. The highest contrast was achieved with the infrared laser and contents of 0.1% carbon black., Financial support from EU project 7FP UV-Marking is gratefully acknowledged (http://www.uv-marking.eu/), grant agreement No 314630.

In this work, the preparation and characterization of MnO2-modified-activated carbon for selective removal of organosulfur compounds including dibenzothiophene were outlined. The deposited particles of the modifier were entrapped within the micropores and the resulting adsorbent was efficient to desulfurize in diesel with rich-sulfur (7055 mgS kg−1). Removal of organosulfur compounds was positively correlated with the deposited MnO2 and the best efficiency was observed at surface loading 30.6%Mn. The comprehensive characterization tests indicated drastic changes in the physicochemical properties of the modified adsorbents. The main findings were: (a) particles of α-MnO2 were accumulated within the microspores and (b) less acidic surface compared to activated carbon was created in all modifications. Scanning electron microscope pictures indicated the filling of the pores by particles of MnO2. The mechanisms of S-compounds removal by the modified adsorbent were elucidated with the aid of Infrared spectral analysis. Adsorption isotherms of dibenzothiophene were measured and the data were presented by different models. Dubinin-Radushkevich model confirmed that adsorption of dibenzothiophene was exothermic and both Jovanovic and Langmuir models indicated the homogeneity of the modified surface. Jovanovic model gave the best prediction of the maximum adsorption capacity. Combustion qualities of deeply desulfurized diesel were found within the regulated limits. © 2017 American Institute of Chemical Engineers Environ Prog, 2017

International audience; We report the mid-IR s-SNOM surface characterization of a chalcogenide glass photo-inscribed by ultrashort laser pulses. Imaging allows to access to the morphology and the optical properties of the material at nanoscale, unravelling topographical and optical contrasts resulting from the laser inscription process. © 2019 IEEE.

Surface characterization and corrosion behavior of 90/10 copper-nickel alloy in seawater from Xiamen bay at 30 °C for 56 days were investigated in this study. The results indicated that the corrosion product layer was mainly a mixture of CuO, Cu2O, and Cu(OH)2, with a transition to CuCl, CuCl2, and Cu2(OH)3Cl during the corrosion process. However, as corrosion proceeds, the resistance of the product film was reduced due to its heterogeneous and fairly porous structures, which led to local corrosion of the alloy. The corrosion potentials (Ecorr) increase while corrosion current densities (Icorr) decrease with time because of the formation of protective oxide film.

The present study investigates the photocatalytic degradation of three quinolone antibiotics (i.e., Flumequine (FLU), Oxolinic Acid (OA) and Nalidixic Acid (NA)) in mono-, binary and ternary compound systems. The closed-loop step photo-reactor and TiO2 impregnated on cellulosic paper as supported photo-catalyst in presence of UV light irradiation were used. The degradation of FLU occurred within 4 h. A 65.4% mineralization of OA was observed in a mono-compound system, due to the fast conversion of these main by-products formed. Besides, the investigation of the contribution of free radicals revealed the involvement of hole (h(+)), O-2(center dot-), but mainly "OH on the degradation of OA. The second-order kinetic rate constants calculated relative to the contribution of (OH)-O-center dot radicals on the degradation of OA was 4.03 x 10(9) M(-1)s(-1), whereas for that of NA was 4.42 x 10(9) M(-1)s(-1), thus underscoring that (OH)-O-center dot coproduct is the primary reactive species implicated in the photocatalytic degradation of these compounds on TiO2/cellulosic paper catalysts. The mono-compound system shows a higher degradation rate compared to multi-compound system (binary and ternary) which explained by the competitive adsorption of antibiotics on the available active sites of photocatalyst surface. Overall, the constant photocatalytic rates are higher following this order: mono compound system > ternary mixture >binary mixture. The catalyst was characterized by mean of FTIR, HR-TEM and XRD. The SiO2-binder role was discussed in details based on the atomic distribution of elements on the cellulose fibers as shown by the EDS atomic mapping. (C) 2019 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.

Performance of a sensing device is dependent on its construction material, especially for components that are directly involved in transporting and translating signals across the device. Understanding the morphology and characteristics of the material components is therefore crucial in the development of any sensing device. This work examines the morphological and electrochemical characteristics of reduced graphene oxide interspersed with poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (rGO-PEDOT:PSS) used as a transducer material deposited on a commercially available screen-printed carbon electrode (SPCE). Electron microscopy shows that PEDOT:PSS is interspersed between rGO layers. Raman and XRD analyses suggest that the graphene crystallinity in GO-PEDOT:PSS and rGO-PEDOT:PSS remains intact. Instead, PEDOT:PSS undergoes a change in structure to allow PEDOT to blend into the graphene structure and partake in the &pi, &pi, interaction with the surface of the rGO layers. Incorporation of PEDOT:PSS also appears to improve the electrochemical behavior of the composite, leading to a higher peak current of 1.184 mA, as measured by cyclic voltammetry, compared to 0.522 mA when rGO is used alone. The rGO-PEDOT:PSS transducing material blended with glucose oxidase was tested for glucose detection. The sensitivity of glucose detection was shown to be 57.3 &micro, A/(mM&middot, cm2) with a detection limit of 86.8 &micro, M.

The surface chemistry of nanoparticles is the key factor to control and predict their interactions with molecules, ions, other particles, other materials, or substrates, determining key properties such as nanoparticle stability or biocompatibility. In consequence, the development of new techniques or modification of classical techniques to characterize nanoparticle surfaces is of utmost importance. Here, a classical analysis technique, thermally evolved gas analysis – mass spectrometry (EGA-MS), is employed to obtain an image of the nanoparticle–solvent interface, unraveling the molecules present on the surface. As the use of complementary techniques is urged, the validity of EGA-MS characterization is corroborated by comparison with a previously reported surface characterization method. Previous studies were based on several experimental techniques and MD simulations using YF3 nano/supraparticles and LaF3 nanoparticles as model systems. We demonstrate the applicability of this technique in two differently sized systems and two systems composed of the same ions on their surface but with a different inorganic core (e.g. LaF3 and YF3 nanoparticles). The results described in this paper agree well with our previous results combining experimental techniques and MD simulations. EGA-MS not only revealed the ions attached to the nanoparticle surface but also shed light on their coordination (e.g. citrate attached to one or two carboxylate moieties). Thus, we show that EGA-MS is a useful and efficient technique to characterize the surface chemistry of nanoparticles and to control and predict their final properties., This work was supported by the Spanish Ministry of Economy and Competitiveness through the “Severo Ochoa” Programme for Centres of Excellence in R&D (SEV-2015-0496), the CONSOLIDER Excellence Network (MAT2015-68994-REDC), and SuMaTe RTI2018-095853-B-C21 and RTI2018-095853-B-C22 projects (both co-financed by the European Regional Development Fund). We also acknowledge the support from the European Union for the EUROTAPES Project (FP7-NMP-Large-2011-280432) and from the Catalan Government with 2017-SGR-1519. The authors acknowledge the technical support of Servei de Microscòpia at the UAB.

Mg-xGd alloys show potential to be used for degradable implants. As rare earth containing alloys, they are also of special interest for wrought products. All applications from medical to engineering uses require a low and controlled degradation or corrosion rate without pitting. Impurities from fabrication or machining, like Fe inclusions, encourage pitting, which inhibits uniform material degradation. This work investigates a suitable etching method to remove surface contamination and to understand the influence of etching on surface morphology. Acetic acid (HAc) etching as chemical surface treatment has been used to remove contamination from the surface. Extruded Mg-xGd (x = 2, 5 and 10) discs were etched with 250 g/L HAc solution in a volume of 5 mL or 10 mL for different times. The microstructure in the near surface region was characterized. Surface characterization was done by SEM, EDS, interferometry, and ToF-SIMS (time-of-flight secondary ion mass spectrometry) analysis. Different etching kinetics were observed due to microstructure and the volume of etching solution. Gd rich particles and higher etching temperatures due to smaller etchant volumes promote the formation of pits. Removal of 2–9 µm of material from the surface was sufficient to remove surface Fe contamination and to result in a plain surface morphology.

In this work, the transport and removal of Cr(VI) were achieved through supported liquid membrane (SLM) by using a 5,17, di-tert-butyl-11,23-bis[(1,4-dioxa-8-azaspiro [4,5]decanyl)methyl]-25,26,27,28-tetrahydroxy calix[4]arene carrier, dissolved in 2-nitrophenyl octyl ether dichloromethane. The studied parameters are the solvent effect in the membrane phase, the effect of carrier concentration, and the acid type in the donor phase. The Celgard 2500 was used as a membrane support. We used the Danesi mass transfer model to calculate the permeability coefficients for each studied parameter. In addition, AFM and SEM techniques were used to characterize the surface morphology of the prepared Celgard 2500 membrane that included the calix[4]arene carrier. © 2018 Elsevier B.V.

Ion micro beam was employed to fabricate microstructures based on poly(dimethylsiloxane) (PDMS). Carbon ions with energy of 6.0 MeV were used. The ion treatment induces modifications in PDMS surface and on the optical properties as a function of the ion current and fluence. PDMS foils were produced from commercially available two component addition materials. The selective modifications of the polymer were studied for applications in micro-fluids, micro-optics and micro-electronics. The comparison between the unirradiated and irradiated PDMS was investigated in morphology and compactness using the atomic force microscopy. The wetting ability of the PDMS surface was also analyzed as a function of the ion microbeam irradiation. The compositional and optical changes in PDMS were monitored by Rutherford backscattering spectrometry, elastic recoil detection analysis and optical spectroscopy measurements.

Research advances in electropolishing, with respect to the field of metalworking, have afforded significant improvements in the surface roughness and conductivity properties of aluminum polished surfaces in ways that machine polishing and simple chemical polishing cannot. The effects of a deep eutectic medium as an acid-free electrolyte were tested to determine the potential energy thresholds during electropolishing treatments based upon temperature, experiment duration, current, and voltage. Using voltammetry and chronoamperometry tests during electropolishing to supplement representative recordings via atomic force microscopy (AFM), surface morphology comparisons were performed regarding the electropolishing efficiency of phosphoric acid and acid-free ionic liquid treatments for aluminum. This eco-friendly solution produced polished surfaces superior to those surfaces treated with industry standard acid electrochemistry treatments of 1 M phosphoric acid. The roughness average of the as-received sample became 6.11 times smoother, improving from 159 nm to 26 nm when electropolished with the deep eutectic solvent. This result was accompanied by a mass loss of 0.039 g and a 7.2 &micro, m change in step height along the edge of the electropolishing interface, whereas the acid treatment resulted in a slight improvement in surface roughness, becoming 1.63 times smoother with an average post-electropolishing roughness of 97.7 nm, yielding a mass loss of 0.0458 g and a step height of 8.1 &micro, m.

The current percolation in polymer-sorted semiconducting (7,5) single-walled carbon nanotube (SWNT) networks, processed from solution, is investigated using a combination of electrical field-effect measurements, atomic force microscopy (AFM), and conductive AFM (C-AFM) techniques. From AFM measurements, the nanotube length in the as-processed (7,5) SWNTs network is found to range from ≈100 to ≈1500 nm, with a SWNT surface density well above the percolation threshold and a maximum surface coverage ≈58%. Analysis of the field-effect charge transport measurements in the SWNT network using a 2D homogeneous random-network stick-percolation model yields an exponent coefficient for the transistors OFF currents of 16.3. This value is indicative of an almost ideal random network containing only a small concentration of metallic SWNTs. Complementary C-AFM measurements on the other hand enable visualization of current percolation pathways in the xy plane and reveal the isotropic nature of the as-spun (7,5) SWNT networks. This work demonstrates the tremendous potential of combining advanced scanning probe techniques with field-effect charge transport measurements for quantification of key network parameters including current percolation, metallic nanotubes content, surface coverage, and degree of SWNT alignment. Most importantly, the proposed approach is general and applicable to other nanoscale networks, including metallic nanowires as well as hybrid nanocomposites.